1. Field of the Invention
The present invention relates to a digital content downloading system in which digital content such as music files, video files, game software titles and so on are downloaded to a plurality of consumers through networks.
2. Description of Related Art
In a current business field using a communication network, the interest of people has been changed from “technology-oriented” to “service-oriented”. In particular, people have paid attention to the Asynchronous Transfer Mode (ATM) as a technique guaranteeing the Quality of Service (QOS) indicating the communication quality. In an ATM network with the appropriate network managing performance, various types of traffic such as the internet protocol (IP), frame relay and voice can be simultaneously processed, and the service quality for the digital content can be easily guaranteed. Therefore, the ATM network is expected as a strong tool for digital content delivery.
Also, if network managing functions of ATM networks are available, a business using networks can be easy by utilizing various QOS classes such as Variable Bit Rate (VBR), non-real time service classes and so on, which means the business becomes “service-quality oriented” instead of “technology-oriented”. For example, to provide a technology service for consumers, a highly-efficient QOS class can be used in stead 6f a simple class of Constant Bit Rate (CBR). The technology of the network management is not only used for the management of hardware such as routers, switches and so on, but also used as a means of “service management”.
This strict service management is feasible because the ATM network has a high-performance QOS managing capability. In the ATM networks, parameters such as a transfer bit rate (which is also called “bandwidth” in this technical field), a delay time, a delay variation, a burst size, a cell interval and a cell discard rate, thus the virtual circuit (VC) can be precisely established with QOS guarantee.
In ATM Forum, QOS characteristics of each virtual circuit are classified, and four service classes are defined. They are CBR class, real time VBR class, non-real time VBR class and available bit rate/unspecified bit rate (ABR/UBR) class.
As is described above, because the four service classes are provisioned in ATM networks, even though congestion occurs in one of the four service classes, the influence of the congestion to the other classes can be prevented. For example, even though the congestion of data traffic occurs in an ATM switch, voice or video traffic belonging to the CBR class can be stably transmitted.
Also, charging of downloading of digital content to each consumer using ATM networks has been studied. To maintain a competitive edge in public network services, a fixed charge for the digital content download is not proper, but a policy of determining a charge depending on a type of the digital content or a downloading quality of the digital content is desired. For example, in many proposals of charging mechanisms, it is applicable that a charge for a CBR service be higher than that for a best effort type UBR service. Also, it is proposed that a charge for digital content be selected by a time zone, or that a charge for the digital content be decided in proportion to a bandwidth used for downloading or a service time zone.
In these proposals, a consumer who downloads digital content is charged in dependence on not only types of the digital content such as music files, video files of a cinema or map and game software titles but also the quality or time of downloading digital content. Therefore, the charging mechanism depending on how to use networks is possible.
However, in the digital content downloading system using the conventional optical access network, though the consumer can specify digital content itself, the consumer cannot specify a quality in the transmission of the digital content transmitting through a subscriber line, but the digital content retailer can specify the transmission quality of the digital content.
Also, in cases where the consumer purchases digital content, the consumer accesses to a digital content retailer possessing the digital content to obtain a data volume of the digital content from the digital content retailer, the consumer reports the data volume of the digital content to a network operator to secure a channel of a subscriber line, the consumer again accesses to the digital content retailer to inform the digital content retailer of the channel of the subscriber line, and the digital content retailer downloads the digital content to the consumer through the channel of the subscriber line. Therefore, there is a problem that the procedure for purchasing the digital content is complicated and troublesome.
Also, in cases where the consumer purchases digital content downloaded at a high quality transmission, in which the digital content is downloaded only for a short time, from a digital content retailer through a network of a network operator, not only the consumer has to pay a charge for the digital content to the digital content retailer, but also the consumer has to pay a charge for the high quality transmission to the network operator. Therefore, there is another problem that the procedure for paying the charges is complicated and troublesome.